module mod_material
  ! a simple version 
  
  real(8),allocatable,save,dimension(:,:,:)::sigma

contains
  subroutine material_setup()
    use mod_grid
    use mod_para
    implicit none
    integer::ierr
    allocate(sigma(nx1-1:nx2+1,ny1-1:ny2+1,nz1-1:nz2+1),stat=ierr);
    if(ierr .ne. 0) then
       write(*,*)"Error in material setup."
       stop
    endif
    sigma=0;
    ! need furthur impliment
    sigma=0.01;
  end subroutine material_setup

  subroutine material_clean()
    deallocate(sigma)
  end subroutine material_clean
end module mod_material




